We will continue to concentrate on cell-cell interactions primarily between corneal epithelium and stromal cells, as a major regulatory mechanism for collagenolysis. Having identified stimulatory and inhibitory factors produced from low density and high density adult corneal epithelium under the influence of cytochalasin B, we will further purify and characterize these substances and also search for natural analogues in wounded corneal tissue which probably utilized the same cell surface receptors as does cytochalasin B. We are pursuing new lines of study opened this year on regulation of epithelial stromal cell interactions and tumor vascularization in the cornea by steroid hormones.